In particular in medical technology, but also in the field of automotive engineering or aircraft construction, there is the basic need to accommodate electric apparatuses and electronic components in so-called protective housings which on the one hand protect the apparatuses and components against external effects such as humidity, dirt and shocks/impacts/vibrations and, on the other hand, effectively prevent the escape of electromagnetic waves from the housing.
Such housings usually comprise at least one installation opening which can be closed with an installation flap or hood.
From the prior art, housings of the previously described kind are well known. Said housings consist of a base plate which has four side walls screwed or welded to its periphery. A housing lid comprises a peripherally surrounding installation frame which reaches over or behind the side walls when the cover is attached. Finally, through-holes are provided on the side walls as well as on the surrounding installation frame, and preferably self-tapping screws or metal screws can be screwed into said through-holes in order to mount the cover to the side walls.
The problem with this commonly known housing construction is that already minute gaps or clearances between the individual housing parts may result in electromagnetic waves escaping from the housing interior. What is more, dust particles and moisture penetrate these “installation gaps” and damage the enclosed components. The latter could in fact be prevented by corresponding sealings, but these are usually made of a synthetic material (non-metallic) and thus are permeable to electromagnetic waves.
In order to provide a housing which is tight against moisture and dust as well as isolated in terms of electromagnetic waves, the individual housing components have to be manufactured with high precision and even the installation is to be carried out with high expenditure. This is why the housing parts have to be provided with tongue-and-groove edges and the holes provided for the screw fixation have to be set so precise that the predefined relative positions are not altered during screwing the individual housing parts. This expenditure in the preparation and installation of the housing parts results in the entire housing becoming expensive and its handling impractical.